The present invention relates to a machine for removing burrs on slabs issuing from a continuous casting installation and which are cut to a desired length by oxygen cutting.
The present invention also relates to a rotor for this type of machine for removing burrs on slabs.
The continuous casting of steel permits obtaining a product which is in the form of a thick strip of steel which has to be cut to given lengths so as to form slabs which are then treated in subsequent rolling operations.
The product issuing from the continuous casting installation is converted into slabs by oxygen cutting by means of a torch which projects its jet in a direction perpendicular to one of the faces of the steel strip. Burrs of molten steel are produced on the face opposed to that receiving the jet.
These burrs, constituted by oxygen-cutting residues, are formed due to the disturbance in the discharge of the cutting residues produced by the expansion of the residual gases on the exit side of the cutting slit.
The effect of this phenomenon causes an adhesion of the undischarged residues on each end edge of the inner face of the slabs.
For the purpose of eliminating these burrs, there is known from FR-A-2 467 041 a burr-removing machine comprising a group of cutting blades carried by a carriage of which the translation along the longitudinal axis of the slab under the lower face of the carriage. After the cutting edges have been put into contact with the face, the oxygen-cutting residues are cut off.
However, this burr-removing machine requires immobilizing the slab for the burr-removing operation. Moreover, it is advisable to provide two opposed symmetrical machines in facing relation to the same face of this slab, respectively for eliminating the burrs at the head end and the tail end of the slab.
This immobilization of each slab is an operation which is extremely detrimental to the productivity of the installation. Furthermore, the presence of two machines substantially increases the cost.
Further, there is known from FR-A-2 580 203 a rotary machine comprising a rotor mounted horizontally in a stand and carrying on its periphery retractable hammers having heads which describe an envelope which is brought to a position substantially tangent to the lower face of the slab.
The machine is placed under the principal lower face of the slab of which the head and tail end edges include burrs, the axis of the rotor being disposed parallel to the face of the slab and at such distance therefrom that the heads of the hammers driven in rotation describe a circular envelope tangent to the lower face of this slab and in this way tear away the burrs projecting from this face.
In this machine, the rotor comprises a hub on which bearing flanges are fixed in evenly spaced apart positions in the direction of the longitudinal axis of the hub.
These bearing flanges receive a group of articulation pins evenly spaced apart on the periphery of the bearing flanges. The hammers are mounted on the articulation pins.
Such a construction provides on the same line a series of successive hammers, in side-by-side relation, except in the region of the bearing flanges.
Thus, the burrs are only torn away in the region of the hammers and not in the region of the bearing flanges.
The burr portions which have not been removed by the burr-removing machine must consequently be torn away manually, for example by means of a grinding wheel.